School of Specs 38.300v19.3.0

3GPP 38.300 v19.3.0 — the document's own text

Annex C I-RNTI Reference Profiles

Taught in 6. The three states a device sits in (TSG RAN — the group that specifies the radio, in depth).

The I-RNTI provides the new NG-RAN node a reference to the UE context in the old NG-RAN node. How the new NG-RAN node is able to resolve the old NG-RAN ID from the I-RNTI is a matter of proper configuration in the old and new NG-RAN node.

Table C-1 below provides some typical partitioning of a 40bit I-RNTI, assuming the following content:

  • UE specific reference: reference to the UE context within a logical NG-RAN node;
  • NG-RAN node address index: information to identify the NG-RAN node that has allocated the UE specific part;

NOTE: RAT-specific information may be introduced in a later release, containing information to identify the RAT of the cell within which the UE was sent to RRC_INACTIVE. This version of the specification only supports intra-RAT mobility of UEs in RRC_INACTIVE.

  • PLMN-specific information: information supporting network sharing deployments, providing an index to the PLMN ID part of the Global NG-RAN node identifier.

Table C-1: I-RNTI reference profiles

Profile IDUE specific referenceNG-RAN node address index (e.g., gNB ID, eNB ID)RAT-specific informationPLMN-specific informationComment
120 bits(~1 million values)20 bits(~1 million values)N/AN/ANG-RAN node address index may be very well represented by the LSBs of the gNB ID.This profile may be applicable for any NG-RAN RAT.
220 bits(~1 million values)16 bits(65.000 nodes)N/A4 bits (Max 16 PLMNs)Max number of PLMN IDs broadcast in NR is 12.This profile may be applicable for any NG-RAN RAT.
324 bits(16 million values)16 bits(65.000 nodes)N/AN/AReduced node address to maximise addressable UE contexts.This profile may be applicable for any NG-RAN RAT.